Ecofriendly synthesis of MWCNTs by electric arc in aqueous medium: Comparative study of 6B pencil and mineral graphite

Abstract

The production of carbon nanotubes (CNTs) by electric arc discharge (EA) usually applies pure mineral graphite (PMG) as the precursor electrode due to its high‐purity and conductivity. This work investigated the versatility of EA in aqueous medium for the production of CNTs by varying the electrodes purity degree. In this way, a variety of domestic and industrial graphite waste can be recycled into high‐quality CNTs by adjusting the EA parameters. CNTs were synthesized using 6B pencil (6BP, ~57% graphite) and their quality and quantity were compared to the PMG (99.995%) production. PMG led to short CNTs (ID/IG 0.266), while the synthesis with 6BP led to long CNTs (ID/IG 0.428). The 6BP CNTs showed elevated quality for application in the electronic, biomedical, and optical fields.

Influence of CVD parameters on Co‐TiO2/CNT properties: A route to enhance energy harvesting from sunlight

“…Lower I D /I G values indicate that the formed CNTs have a higher degree of graphitization, fewer defects, and, consequently, higher quality. 47 Therefore, shorter synthesis times and temperatures can be considered more suitable to obtain higher quality nanotubes. Less defective CNTs perform better in photocatalytic applications due to their electrical conductivity.…”

“…The I D /I G ratio is associated with the carbon graphitization degree and is used to determine the quality of the CNTs. Lower I D /I G values indicate that the formed CNTs have a higher degree of graphitization, fewer defects, and, consequently, higher quality 47 . Therefore, shorter synthesis times and temperatures can be considered more suitable to obtain higher quality nanotubes.…”

The effect of CaCO3 in the formation of carbon nanotubes via electrolysis of molten Li2CO3/CaCO3 mixtures

“…The I D / I G ratio is associated with the degree of carbon graphitization (conversion of amorphous, semi‐ordered, or free carbon into a three‐dimensionally ordered graphical structure). A high degree of graphitization means high quality and quantity of CNTs 19 . Therefore, a greater degree of graphitization is associated with a lower I D / I G ratio.…”

“…A high degree of graphitization means high quality and quantity of CNTs. 19 Therefore, a greater degree of graphitization is associated with a lower I D /I G ratio. Table 1 presents the variation of the I D /I G for the various synthesis conditions.…”

“…2,4,5,[14][15][16] Since the first synthesis of carbon nanotubes (CNTs) was elucidated by Iijima (1991), 17 the scientific community has been searching for methods that allow the production of these nanostructures in a controlled manner and with high quality. CNTs are currently synthesized by technologies such as plasma, 18 electric arc, 19 and chemical vapor deposition 20 techniques. However, the demand for these products is still limited, mainly due to the complexity and the cost involved in production, and consequently adding cost to the final product, they are currently valued at $85 000-$450 000 per ton.…”